The present disclosure relates to methods of reducing inflammation around a chronically implanted medical device by coating the device with a polymer/lipoic acid conjugate. This conjugate is particularly useful for coating an electrode which is inserted into the brain, as neurodegeneration around the electrode is reduced, thus permitting neural signals to be recorded by the electrode for an extended period of time.
Neural signal recording failure from chronically implanted neural electrodes is a major issue that limits the widespread deployment of such devices for rehabilitation related applications where the recording of brain signals is useful or necessary. It is widely hypothesized that glial scar, which is a result of the body's immune response to the “foreign” electrodes, electrically impedes the recording ability of the electrodes.
Recently, it has been suggested that the presence of electrodes in brain tissue creates a chronic inflammatory state which causes neurodegeneration (loss of neuron function) and can lead to implant failure. Reactive oxygen species (ROS) such as hydroxyl and superoxide radicals may play an important role in the initiation and progression of chronic inflammation around the electrodes.
It would be desirable to reduce inflammation and neurodegeneration around chronically implanted devices, such as electrodes, in the brain. More generally, reducing inflammation around a chronically implanted medical device may be desirable as well.